1. Field of the Invention
The present invention is related to a side view image input device which is used as an internal examination scope found in dental scopes and equipment.
2. Description of the Related Art
There have been proposals for side view dental scopes for dental treatment which make visible the status of any tooth and gum portion positioned within the oral cavity in locations which are difficult to see; and a CCD element is incorporated for taking photographs of this.
In this type of dental scope, a light projection window forms an opening to the tip side surface of a lens barrel; and arranged along the optical axis are: a side view mirror, which reflects the optical image incident from a side translucent part to face the lengthwise direction of the lens barrel; an image focusing optical system, which focuses that image by a specified magnification; and a CCD element, which captures the optical image focused by that image focus optical system. In addition, industrial side view type scopes also have the same structure.
Then, when used as a dental scope, if the lens barrel is inserted into the oral cavity, etc. and the translucent window is made to face the location to be seen, an image of part of the teeth or gums can be photographed by the CCD element, and therefore this can be projected on a television monitor.
Nonetheless, in this situation, because it is necessary to bend the light route at a right angle utilizing the reflection of the side view mirror or a prism in order to see the side surface of the lens barrel, the image which is projected onto the television monitor is inverted top to bottom, left to right, and there is the concern that the user will experience an optical illusion.
Moreover, once the image signal obtained by processing the signal that is output from the CCD element is memorized, if the left and right of the image is inverted by reversing them synchronously with the horizontal scan signals, the correct image can be projected on the television monitor without left to right inversion, but there are the problems that that image signal inversion circuit is complicated, and the costs are increased.